Connecting film ends



Sept. 29, 1942. H. WESTERKAMP CONNECTINGFILM ENDS Filed April 18, 1959 I Invnior: a, @W

PatentedhSept. 29,194?

Hugo 'Westerkamp, Cologne-Braunsteld, Germany; vested in the Allenlroperty Custodian Application April 1a; 1939, Serial no; 268,646

In Germany May 6,1938 6 2 Claims. (01. 154-42) The invention relates to an arrangement for connecting under pressure two film ends coated with a solvent, the connecting of two film ends including in particular a sticking together of two film ends which is eflected by applying to the adjacent surfaces of two film ends laid one upon the other a solvent which "dissolves the film material, while the film ends. are placed under pressure, it necessary with the application of heat, until the double film thickness has been reduced to the thickness. of. a single-film by compression, while the surplus dissolved film material flows away:

The object of the invention is arrangement by the use of which the film-ends are connected durably in a manner which is satisfactory in all respects, and which ensures in particular that the film also remains quite flat at the connecting point.

According to the invention, this is achieved with an arrangement for, pressingthe film ends toto; provide an I gether during the connectionthereof; This-arrangement comprises .twoclamping jaws which are pervious to' air .and exertlthe connecting pressure, andis based upon the fact that the film ends are connected together-in a really satisfactory and durable manner andth'e filrmalso but only if the'solvent has sufllcient opportunity the application of the pressing to escape during force.

force by which the film ends are pressed together is efiective over the entire surface during the remains completely fiat-at'the'connecting point,

lose acetate,- cellulose nitrate or cellulose hydrate, and upon the solvent employed, which may be; for example, glacial acetic acidor the like, and may be determined readily by experiment. Since the escape of the solvent from the film connecting point is substantially a function of the physical conditions-of the surroundings, the clamping jaws are surrounded, according to the invention, by a chamber provided with an arrangement for" regulating the degree of. th absorption'orthe solventbythe air, it being possible to efiectthis regulation in a known manner.

The drawing illustrates diagrammatically a construction of. an arrangement according to the invention, by way of example. The two film' ends to be connected together are designated by- I and 2.. They are coated with a solvent and are either laid directly one upon the other as shown and so pressed together that the surplus material flows away, or they may, for example, b oppositely bevelled at their-edges whichare connected and joined together by pressure.

The pressing force is exerted by two clamping jaws 3, 4, the direction of pressure being indi cate'd by arrows, in thedrawing. 'The. clamping laws are so fashioned that they assist the escape of the film solvent from the film connectingpoint and the evaporation and withdrawal of the sol-'- vent. For this purpose, the, clamping jaws, which are'planeground on theirclamping surface, are made pervious-to air, the clampingiaws preferablyIbeing-jtraversed by a plurality of fine channelswhichiorm, a communication between the escape of the solvent. According to the-invention, thisisbest achieved it the clamping laws are traversed-by a plurality of finechannels form ing communication between the clamping surface and the outer surface of the clampingia'ws; in

particularthe rear surface thereof; Howevea'it.

is not essential that this communication should be direct, but the object of the invention can also 1 be achieved with clamping jaws consisting ofa material of spo y structure. Bothamaterial traversed by fine channels and a ma-- terial have, when ground plane, a large-effective pressure suriace having many air channels through which the solventescapes without too.

, rapid an escape, thereof having'tobe-feared.

The favourable period during which the film ends coated with .the solvent should be maintained under pressure and during which the solvent escapes, depends upon the film material em- 7 v ployed, which may consist, iorexampla-ot cellu-v air may be taken in through an aperture 6 in clampings'urfalce and the outer surface of the clamping jaws, in particular their rear surface. In the drawinasthese channels are diagrammatically represented in section by a fewv rectilinear channels, .but' the number of ,channels in the individual cross-sectional plane may be'considerabiy greaterth'an that'showmwhlle finely reticulate .channels'maybe employed, instead of rectilinea'rchannels. A material of spongy structure, namely a material having a plurality of small interstices separated Irom one another by partitions, through which the solvent may.

readily be diffused, is'suit'able for producing the clamping jaws The clamping jaws are surroundedby a cas ing 5 in which the degree ofabsorption of the solventby the air, is regulated. This regulation example, the absorption, of the solvent by the" i, air is, a functionoithemoisture of the air, fresh content of the said air-being regulable by means of drying dishes I. The surplus air may escape at 0. However, the absorption or the solvent by the air may also be regulated in very many other ways, tor example by directly feeding solvent to, or extracting solvent from, the air in the chamher.

I claim:

1. Device for connecting the ends of lengths of film, comprising a housing and two compression jaws located in the housing and between which the ends oi! the film lengths may be inserted in overlapped condition with a film solvent therebetween and by which Jaws the overlapping portions may be compressed to the thickness of a single film and from between which the excess material may escape, said jaws having smooth. rigid and substantially plane surfaces for compressing engagement with the film lengths and having a porous structure throughout the area of overlapping formed by a multiplicity of closely spaced fine channels through which evaporated solvent may be gradually withdrawn directly from the contacted surface and discharged through the structure to the interior of the housing, said housing having openings in alignment with the Jaw surfaces and through the casing i by means of a fan I, the moisture which the ends of the film lengths may be introduced into the space between the Jaws.

2. Device for connecting the ends of lengths of film, comprising a housing and two compression jaws located in the housing and between which the ends 01' the film lengths may be inserted in overlapped condition with a film solvent therebetween and by which jaws the overlapping portions may be compressed to the thickness of a single film and from between which the excess material may escape, said jaws having smooth, rigid and substantially plane surfaces for compressing engagement with the film lengths and having a porous structure throughout the area of overlapping formed by a multiplicity of closely spaced fine channels through which evaporated solvent may be gradually withdrawn directly from the contacted surface and discharged through the structure to the interior of the housing, said housing having openings in alignment with the Jaw surfaces and through which the ends of the film lengths may be introduced into the space between the jaws, means for delivering vapor to the atmosphere within the housing whereby to regulate the rate of withdrawal of solvent through the jaws, and means for passing air through the housing.

HUGO WESTERKAMP. 

